Fiber Optic Affinity Ligand Sensor for Quantification of Ultra-Trace-Level Fuel Contaminants

F&S and their research partners propose a comprehensive plan to develop a fiber optic-ased chemical detection system for the quantification of metal contaminants in aviation fuel. The system will utilize recently developed long-period grating (LPG) technology which detects index-of-refraction changes resulting from target molecules binding to affinity coatings. Calculations based on experimental results indicates an LPG-based chemical sensor sensitivity in measurements to parts-pertrillion (ppt). In the past, metalloenzymes such as carbonic anhydrase have been used in fluorescent-based fiber optic sensors (Thompson and Jones, 1993). However the sensitivities reported were only in the nanomolar range, and required the binding of a fluorescent molecule after capture of Zn (II). We emphasize here that with a metal affinity LPG sensor, we can achieve 10 to 1000-fold greater sensitivities by direct loading of a sample, and without additional fluoresent label binding steps. Hence, less bulky device designs which do not have concentating, pre-purification, and ion-based mass spectrometric detectors are achievable. It will therefore be possible to integrate the chemical LPG sensor into a portable, operated by a technical with minimal training.